Administrative

Vision

Directions. Complete all of the following tests. Record you results on paper and transfer to the survey. Answer the questions posed by the instructor in the quickwrite. Discuss the results as directed by the instructor.

Blind Spot

1. Close your right eye2. Look at the cross with your left eye and slowly move your head toward the screen3. You should see the black dot disappear

4. Measure the distance from your eye to the screen.

Eye Dominance

Extend your arms in front of you with your palms facing away.Bring your hands together, forming a small hole by crossing the thumbs and fore fingers.Choose a small object about 15-20 feet away from you. With both eyes open, focus on the object as you look through the small hole.Close one eye and then the other. When you close one eye, the object will be stationary. When you close the other eye, the object should disappear from the hole or jump to one side.If the object does not move when you cover one eye, then that eye is dominant. The eye that sees the object and does not move is the dominant eye.

Color Vision

Color vision is the ability to distinguish wavelengths (or frequencies) of the light. Human perception of colors is a subjective process whereby the brain responds to the stimuli that are produced when incoming light reacts with the several types of cone photoreceptors in the eye. The three primary colors of light are red, green and blue. Using colored lamps (or the color mixing gizmo in Explore Learning, determine the colors obtained by mixing the three primary colors. What do you get when you mix red and green? Blue and Green? Red and Blue? Red, Green and Blue?

Retinal Fatigue

Cover one eye, then stare at the center of the flag for one minute. Keeping your eye focused on the screen, click on the flag and stare at the white screen. What color replaces black? What color replaces cyan? What color replaces yellow?

Color Blindness

Click on the image below to enlarge. Record the numbers or letters that you see in each circle.

Perception

Perception is the organization, identification and interpretation of sensory information in order to represent and understand the environment. Perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs. The study of illusions and ambiguous images demonstrates that the brain's perceptual systems actively and pre-consciously attempt to make sense of their input. What is the first thing you see in each of the following images?

Visual Acuity

Download and printout the attached Snellen Chart. This Snellen Eye Chart should be printed on regular 8.5 x 11" paper and should be read while standing 2.9 meters (9.5 feet) from the chart. Be sure you are in a room that is well lit. Test one eye at a time By covering the other eye with your hand. The lowest line that you can read correctly is your visual acuity.

Astigmatism

An astigmatism is a condition due to irregular curvature of the cornea or lens. Astigmatisms cause blurring and can be detected using the charts below. Click on the chart to enlarge. Close your right eye and concentrate on the image with your left eye then cover your left eye and concentrate on the image with your right eye. If the lines do not appear equally bold, you probably have an astigmatism. Repeat the procedure with corrective eye-ware and report your results in the survey.